6 hp tohatsu stalls

[cat22]

I have a 3 year old tohatsu 6hp extra long shaft for my sailboat. Has run great till about a month ago. I was going out, the motor had been running for about 10 min. when it suddenly stalled. I was able to restart it easily but when I put it back in gear it bogged down and stalled. It did this several times but I made it to the lake and sailed for an hour or so and it restarted but stalled again several time when put in gear. I managed to finally get it to run long enough to dock. I read on this forum and others about this problem and it seemed a carb cleaning was in order. I also read that some had used SeaFoam with success. I tried that a few days later. I ran rough for a few min. then it ran OK. I made sure it was securely tied to the deck and put it in gear forward and reverse. Ran OK. For the next month everything was OK.
Then Monday the same thing as above happened. Restarted OK, usually on the first or second pull. We sailed for an hour and came in. This time it bogged down once but we got back without incident.
This evening same thing happen after running about 10 min. This time I couldn't get it restarted for about 10 min. Cranked my guts out. Finally restarted and I let it run a while. As soon as I put it in gear it stalled. I did this repeatedly. Every time it stalled immediately or ran for only a few seconds and stalled. Fortunately, we were upwind of the marina and managed to get back OK. Also, this time it was backfiring quite a bit. When it started and almost started and when it stalled. Never did that the previously.
Any ideas on the problem? Fuel pump and filter seem to be OK. I pulled the motor and have it at home now. I have a stand and a large container which I use in the spring to test it out so testing won't be a problem but do I need a carb rebuild kit? Filter? I haven't check the plug yet but last month I did when this started and it was OK. Seems to be a fuel problem.

 

[Mark SF]

Re: 6 hp tohatsu stalls

My 1 year old Tohatsu 3.5 4-stroke has been having similar problems, stalling in gear, rough and wandering idle, stalling when throttle opened.

However last night I fixed it. Poured both gas cans into the Jag, drained the fuel tank on the o/b, refilled everything with new Shell 93 with Stabil in it. It now runs as sweet as could be, and I will now have to turn the idle back down!

Gas was no more than 6 months old, but it had gone off. I am also going to be more careful about running the carb dry when done for the day.

How old is your fuel?

 

[TOHATSU GURU]

Re: 6 hp tohatsu stalls

Fuel over 30 days old should not be used in your outboard...Pour it into your car and use it up that way and a detailed carburetor cleaning usually solves 90% of all of these types of symptoms.

 

[pvanv]

Re: 6 hp tohatsu stalls

Fuel over 30 days old should not be used in your outboard...Pour it into your car and use it up that way and a detailed carburetor cleaning usually solves 90% of all of these types of symptoms.

YES... many of these symptoms are caused by semi-stale fuel. In more severe cases, varnishing of the small passages of the carb (caused by evaporating fuel) is a cause. In one MFS4 I did this week, there was actually white powder oxidation in the carb passages. That forced a new carb, as the oxidation does not dissolve with organic solvents.

 

[cat22]

Re: 6 hp tohatsu stalls

Tried the easiest route and it worked. I had the Outboard on my homemade motor rack in a bucket of water and couldn't even get it to start. So I drained the about 3 month old gas out of the tank, drained the carb and got fresh gas. It started on the 3rd pull. I ran it for 40 min, put it in forward and rev. No stall.
It seems to like the cheap 87 E-10 gas better than the premium 89 octane marine grade gas. First 2 year I used the cheap stuff and it worked flawlessly. This year I splurged and gave it marine grade. If only I could get my wife to like the cheap stuff better than the premium.
Thanks to all for your help.

 

[pvanv]

Re: 6 hp tohatsu stalls

You may have purchased fuel with water in it from the station. Have seen that occasionally. 87 octane is fine, BTW.